Lighting system



r A. E. NOBLE LIGHTING SYSTEM Dec. 10, 1935.

Filed July 26, 1935 Patented Dec. 10, 1935 LIGHTING SYSTEM Aubrey E. Noble, Snyder, N. Y., assig'nor to Day-- lite Tubes, Inc., Buffalo, N. Y., a corporation of New York Application July 26, 1933, Serial No. 682,311

20 Claims. (01.176-124) This invention relates to lighting systems for gaseous illuminating tubes of the alternating current type.

This application is in part a continuation of my copending application, Ser. No. 671,882 filed May 19, 1933, and patented March 5, 1935, No. 1,933,- 111. In said prior application I disclosed a transformer of the high reactance or leakage type hav ing the ends of its secondary winding connected to the anodes of an alternating current type of a gaseous illuminating tube, with a condenser connected across the anodes of that tube to increase the power factor. The present invention relates to the use of such condenser, together with an improvement on thedisclosure of said prior application to eliminate difliculty experienced in the circuit of that prior type of tube because of occasional anode flashing or arcing from one anode to another. This anode flashing is highly objectionable, in that it causes disintegration of the anodes and the electro deposition of the metal or other substances, of the anodes on the adjacent walls of the tubes. The anode flashing also interferes with the normal flow of current from the anodes to the cathode, and frequently causes stoppage of this current and extinguishment of the light.

An object of this invention is to provide an improved lighting system for gaseous illuminating tubes with which the tubes will continue to operate throughout a maximum possible range of supply line voltage variations, and with which a high power factor and maximum efficiency and flexibility of the circuit may be obtained.

I Another and more specific object of this invention is to provide an improved lighting system for gaseous illuminating tubes of the alternating current type; with which anode flashing will be prevented; with which disintegration of the anodes will be largely prevented; with which the tube may be operated otherwise in the usual manner; with which dependable and uniform operation of the tube may be obtained; and which will be relatively simple and inexpensive.

Various other objects and advantages will be apparent from the following description of an embodiment of the invention, and the novel features will be particularly pointed out hereinafter in connection with the appended claims.

In the accompanying drawing, I have illustrated diagrammatically an improved lighting system for gaseous illuminating tubes, constructed in accordance with this invention and illustrating one embodiment thereof.

In this illustrated embodiment of the invention,

I employ a transformer of the leakage or high reactance type, and having a primary winding I which may be connected to power supply lines 2 and-'3 through suitable-control switches 4. The transformer also includes a pair of secondary coils 5 or windings 5 and 6 which are connected in series to one another, such as by wire 1.;

I also employ a gaseous illuminating tube 8 of the alternating current type, having a plurality of anodes 9 and I0 and a cathode I I. The cathode 10 II is shown as of the heated filament type, the heating current therefor being obtained by connecting the ends of the filament to a transformer winding I 2 which is disposed-in inductive relation to the primary winding I. tube 8 is connected by a wire I3 to one side of a choke coil I4, and the other side of thecoil I4 is connected by a wire I5 to the wire I which connects the secondary windingsv 5 and 6. I

. I have found it feasible to include in series in the wire I3 another gaseous illuminating tube I6 of the direct current type, so that the tube I6 will be connected in series with the alternating current type of tube 8, andwhen so connected, the current, which is rectified in tube8, will pass through and operate the direct current tube I6. The tube I6 is provided with an anode I1, and a cathode I8 of the heated type. This cathodemay be of the filament type, similar to the filament cathode II, and is similarly energized by current conducted thereto from another secondary winding or coil I9 which is also disposed in inductive relation to the primary winding I.

Toplace the tube IS in series in the wire I3, the wire I3 is broken, preferably at a. point between the choke coil I4 and the filament I I. The anode I! is then connected'to that portion of the wire I3 which leads directly to the filament I I, and the other portion of the wire I 3 is connected to the cathode I8. The secondary winding or coil 40 5 is provided with an intermediate tap 20, which is connected to one of the anodes such as 9, and the secondary coil or winding 6 is similarly-provided with an intermediate tap 2| which is connected to the other anode ID of the tube 8. The outer end of the secondary coil 5 is connected by a wire 22 to one side of a condenser 23, the other side of the condenser being connected by a. wire 24 to the free or outer end of the secondary coil '6.

It will be observed that the two secondary coils 5 and 6 are connected in series to one another and that the total voltage output of these two coils is impressed upon thecondenser 23.- It will be noted that the taps 20 and 2| are intermediate taps and, therefore, the voltage delivered by each 56 The cathode of the 15 coil 5 and 6 to its respective anode 9 or III will be less than the total voltage output of the coil. The voltage impressed upon the tube 8 at any one time will be only the voltage induced in either coil 5 or 6 between the intermediate tap or 2I and the wire 'I which connects the secondary coils in series.

When current is applied to the primary winding I of the transformenby the closing of the switches 4, current will be induced in the secondary'coils or windings 5, 6, I2 and I9. The current induced in the coils I2 and I9 will heat the cathode filaments II and I8, and the current induced in the secondary coils 5 and 6 will be impressed upon the tubes 8 and I6. Before current will flow through the tubes, however, it is nesessary to ionize the gas therein, and this may be accomplished in any suitable manner.

One manner of ionizing the gas is disclosed and claimed in my prior copending application, Ser. No. 633,106, filed September 14, 1932, and another form is disclosed in my copending application, Ser. No. 671,882, filed May 19, 1933. An-

other form is disclosed'and claimed in the prior application of Howard M. Cavanaugh, Ser. No. 671,886, filed May 19, 19-33, and in the drawing of the present application I have illustrated a starting tube 25 to ionize gas in. the illuminating tubes, in themanner described in the prior applicationof Howard Cavanaugh above identified. This starting tube 25 includes a gastight envelope, tube, or casing, exhausted to a high vacuum, such as to approximately 0.1 microns of mercury pressure. All parts of the envelope or starting tube and contents are thoroughly degasified to remove impurities.

Within the tubeis mounted a relatively fixed contact 26 and a second contact 21 which is resiliently urged intoengagementwith the fixed contact 26. For this purpose the contact2'I may be mounted on a-spring arm 28 disposed within the envelope or casing 25, and the free end of this arm also carries a magnetic armature 29. A wire 30 connects one of the con-' tacts, such as 21, through its mounting arm 28,

- 8 and I6 are ionized. Since the contact 21 is yieldingly and resiliently. urged into engagement with the contact 26, a circuit will be established from one end of the secondary coil 6 through-the contacts 26 and 2I,-wire 3I, wire I3, choke coil I4, and wire I5, back into the other end of coil 6. The current flowing through coil I4 willenergizeit. The armature 29 of the movable contact 21 is disposed in magnetic relation to the choke coil I4, and, hence, when the coilis energized, it will attract the armature 29' and separate the contacts 26 and 21.

When the contacts separate in this manner, theyopen the circuit through the choke coil,- whereupon a momentary surge of current passes through the coil I4, andv since this surge. can not be discharged through the envelope or tube 25 by reason of the separation of the contacts 26 and 21, and the high vacuum in the envelope 25, it will pass through the lighting circuit including the tubes 8 and I6. This momentary discharge of current through the tubes 8 and I6 ionizes the gases therein .and since the lighting current is already impressed upon the tubes ready to flow, the lighting current will immediately flow through the tubes 8 and I6'following the ionization of the gases therein.

When this current flows through the lighting circuit, the choke coil I4, which is in series in the lighting circuit, will again be energized and will attract the armature 29 and keep the contacts 26 and 21 separated. I find it advantageous to insert a resistance 32 in series in the wire 3| to limit the amount of current passing through the coil I4 and which must be broken by separation of the contacts 26 and 21.

The electrical lighting circuit, according to this invention, is very eflicient for gaseous tube work, and especially so when a multiple anode tube is used to rectify an alternating current because the whole system is in a balanced state. balanced By state, I mean that each secondary coil 5 and 6 is delivering energy. only for a fraction of each cycle. The transformer is designed to give a certain current output from the secondary coils 5 and 6 when they are short circuited through an ammeter, and, for that reason, it is known. as of the high reactance or leakage type. The amount of current is regulated by the insertion of laminated steel shunts placed between the primary and secondary coils, allowing a slight air gap to be present on the top and bottom of the shunts, and the yoke and center core of the magnetic circuit of the transformer. These air gaps prevent magnetic saturation in the shunts and reduce local heating.

The secondary coils 5 and 6, or rather those portions connected across the anodes, generate a voltage which is insufficient to maintain a predetermined current value through the tubes 8 and I6 without theme of a condenser, and in order to raise the voltage and the current, I provide the condenser 23 across the ends of the secondary coils 5 and 6, and this condenser 23 increases the power factor and voltage. When the condenser V 23 is provided across the secondary in this manner, an oscillating circuit is established.

Heretofore, the wires 20 and 2I were connected to the extreme ends of the secondary coils 5 and 6 and when so connected, it occasionally happended that the-inductance, resistance, reactance, and capacity of the circuits through the secondary coils 5 and 6 were so corelated that when the tube was lighted, the-circuit was brought into resonance. When the circuit became resonant, I found that very high. peak voltageswere sometimes reached that were sufiicient to cause a discharge to take place directly between the anodes, thereby short circuiting the main part of the circuit through the tube and causing the light to be extinguished, but with the are between the anodes continuing. ,I have found that increasing the distance between the anodes ,so as to ofler a greater resistance to the arc path is not a remedy to prevent anode arcing when the circuit was in resonance or nearly so, and also that constricting the glass of the tubes around the anodes of the tube would not give any relief against; anode flashing.

I have found that carbon of the highest purity is best suited for anode materialby reason of the fact that it will not emit electrons when raised in temperature by the operation of the tube. Any metal will emit electrons provided it is raised sufficiently in temperature and, fo'r'that reason, it can not be used successfully in a gas filled,

multiple anode, rectifier tube. The substitution of carbon as the material of the anodes does not alone preventanode arcing or flashing however.

By placing the condenser in series with the secondary of a high reactance transformer, one can raise the voltage of that circuit an amount which depends onthe electrical characteristics of the circuit. I have found that one microfarad capacity for the condenser was satisfactory in some cases and that inother cases it was necessary to have 8 microfarads or more, depending upon the transformer design, its coil inductance, resistance, and reactance in order to deliver certain desired voltages and currents through the tubes. For example, a certain transformer, when connected to a 110 volt, 60 cycle current, delivered from the secondaryswinding 350 volts without any condenser, which just lighted a tube, but; when the tube lighted, the voltage dropped immediately to 260 volts and the current flowing was approximately 0.5, amperes. In such a case,the power factor was 57 percent.

When a 1.5 MFD condenser was placed across the anodes, the voltage of the secondary coils immediately increased to 460 volts, open circuit, and when the tube was lighted, the voltage was 408 with a current flow of 1.? amperes and a power factor of 92 percent. Similar values are obtained with large output transformers when increased current through the tube is desired, but in every case they'produce a high power factor and a wide range of flexibility and operatingvoltage. By this I means that if the circuit is correct, a transformer normally designed for 110 volts on the primary can suffer areduction in voltage impressed on this primary as low as '75 or 80 volts, without dangerthat the tubes will cease to be lighted, and even at this reduced volt-v 30 percentchanges the volts and amperes in the illuminating tube only about ten percent, but,

without the condenser 23, almost no flexibility is present. The flexibility feature is very important, because in commercial circuits severe surges are sometimes the cause of suspended lighting in gaseous illuminating tubes, until proper voltage is again restored, and unless there is ample voltage range, the tubes will go out or become extinguished for each slight reduction in voltage, but this circuit which is herein described and illustrated gives satisfactory relief in this respect. As above explained, the' condenser 23 may be placed directly across the anodes, andthe circuit has functioned satisfactorily in some instances, depending uponthe resonant point of the completed circuit. I have found instances where the circuit is apparently stable. with the condenser directly across the anodes, and other instances where such .an arrangement was so detrimental that the anode arcing ;or flashing was very severe, and the tubes did not continue lighted because the circuit came into resonance when the load was applied to the tubes.

Serious trouble has been encountered with some installations using such a circuit, this resonant peak developing after the tubes had been installed and operated for several hours, and this is believed to be dueto thefact that the tubes became thoroughly aged during such operation, and the gas therein became verypure; also that the heat vaporized the mercury if that metal was used in the tubes. The heat increases the'pressure in the tube and assists in bringing the circuit into approximate resonance, with the resultant anode flashing. T X

In order to stop-or prevent this resonant condition, I propose to modify the conditions" of the lighting circuit in a mannerto prevent the 5 circuit from being brought into resonance, at starting or during operation. For example, among the factors influencing resonance, and which may be changed may be mentioned resistance, reactance, capacity and inductance, etc. 10 I have found that anode flashing can be satisfactorily prevented or eliminated in a simple manner, by inserting in the condenser circuit across the anodes something which will change the resonant point of the circuit and preferably 15 to a point materially different from that of the lighting circuit through the secondary coils and the tubes. For example, I may insert a choke coil in series in the condenser circuit andthismay be easily done by connecting the wires 20 and 2| 20 to intermediatetaps or turns of the secondary coils 5 and 6, instead of to the ends of thosecoils, so that the induced voltage applied across the anodes will be less than the total amount induced in the complete coils 5 and 6. 2 5

The extra turns of theftransformer coils 5 and 6, which are thus included in series *in the con-,- denser circuit, will function as small choke-coils which materially modify'the point of resonance of the condenser circuit and thus avoid'the bring- 30 ing of the circuit into resonance when a lighting current is applied to the tube or tubes; I have found, for example, that the anodes may be connected to a point on the secondary windings or coils 5 and 6 about 30 percent distant from the 35 terminals connected to the, condenser, so that the condenser voltage will exceed the anode voltage by approximately this difference in the secondary coil winding. v 7

With such an arrangement it, will be readily 40 seen that before anodeflashing can occur, the lighting circuit must not only be in resonance but the condenser must discharge across the .anodes, and this discharge does nottake place by reason of the choking effect of the turns between 5 the condenser and anode connections. Thus, it will be difficult tomake this improved circuit resonant, and it can be made permanently stable in this manner without losing the highjpower factor benefits or flexibility range. Obviously, other changes in the condenser and anode circuit and affecting resonance of the circuit may be made to prevent resonance being established in the lighting circuit.

This particular circuit, which has been herein 55 described and illustrated, is an important "development in the gaseous illuminating tube art, because with it, it is possible to eliminate anode chokes, power factor corrector windings, etc. and the weight, size and cost of the transformer'is c0 reduced, yet maximum flexibility, high power factor, and high efficiency are obtained. This is a decided improvement, and changes what heretofore has been an unsatisfactory, and frequentlya freak, circuit into a successful and depend- :5 able circuit and system.

It will be obvious that various changes, in the details, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.

I claim: v

1. In a lighting systemfor a gaseous i1luminating tube of the alternating current type using a plurality of anodes and a cathode, the combination with said tube of a transformer of the high reactance type and having'aprirnary winding, 'andtwo secondary windings connected in series, leads for said primary winding for supplying thereto an alternating current, a condenser connected acrossthe open ends of the series-connected secondary windings, means electrically connecting said cathode to the connection between the secondary windings, and means connecting said anodes to said secondary windings, one to each winding at an intermediate point therein, whereby the additional secondary turns in the condenser. circuit will produce a choking effect therein and prevent anode flasliing.

2. In a lighting system for a gaseous illuminating tube of the alternating current type using a plurality of anodes and a cathode, the combination'with said tube of a transformer of the high reactance type and having a primary winding, and two secondary windings connected in series, leads for said primary winding for supplying thereto an alternating'current, a condenser connected across the open ends of the series-connected secondary windings, means elee trically connectingsaid cathode to the connection between the secondary windings, and means connecting said anodes to said secondary windings, one to each winding at an intermediate point therein, and about 30% from the'connections to the condenser, whereby the additional secondary turns in the condenser circuit will pro duce a choking effect therein and prevent anode flashing. r g j 3. In alighting system fora gaseous illumi nating'tube of the alternating'current type us- 4.In a lighting system for a gaseous illuminating tube of the alternating current type using a plurality of anodes and a cathode, the

combination with said tube of a transformer, a source of primary current for said transformer, connections from said transformer to said cathode and said anodes for delivering thereto a lighting current, a condenser, and connecting means from said transformer to said condenser for delivering. to said condenser a secondary'voltage about 30% different than that delivered to said tube, whereby anode flashing in said tube will be prevented.

5. In a lighting system for a gaseous illuminating tube of the alternating current type-using a plurality of anodes and a cathode, the combinationwith said tube of a leakage, reactance type transformer, a source of primary current for said transformer, connections from the secondary of said transformer to said cathode and said anodes for delivering thereto a lighting current, a condenser, and connecting means from the terminals of the secondary of said transformer directly to said condenser and having therein means for varying the resonance of the condenser circuit, for establishing therewith a high power factor in said primary current, and maintaining an approximately -uniform anode voltage-under wide variations in the voltage of said primarycurrent, whereby anode flashing will be prevented.

6. In a lighting system for a gaseous illuminatin'g tube of the alternating current, rectifying type using a plurality of anodes and a cathode, the combination with said tube of a leakage reactan'cetype transformer, connections for delivering a' service supply current-to the primary of said transformer, connections from different turns of the secondary of said transformer to said anodes, and from said cathode to a turn of said secondary approximately midway between said different turns for delivering to said tube an induced lighting current, a-condenser circuit also connected directly across the secondary winding and having resonance varying means therein for maintaining an approximately uniform anode voltage under wide variations in the voltage of said service-supply current, and also maintaining a high power factor in said service supply current. a

L 7. In a lighting system fora gaseous illuminating tube of the alternating current, rectifying type using a plurality of anodes and a cat-hode, the combination with said tube of a leakage, reactance type transformer, connections for delivering a service supply current to the primary of said transformer, connections from different turns of the secondary of said transformer to'said anodes, and from said cathode to a turn of said secondary approximately midway between said different turns for delivering to said'tube an induced lighting current, and means including a condenser also'comiected to the secondary' winding in parallel to said anodes and forming with the secondary a condenser circuit having a materially different impedance than that of the'frequency circuit including the secondary and said anodes for maintaining an approximately -uniform anode voltage under wide variations in thevoltage of said service supply current, and also maintaining a high power factor in said service supply current.

8. In a lighting system for a gaseous illuminating tube of the alternating current, rectifying type using a plurality of anodes and a-cathode, the combination with said tube of a leakage, reactance type transformer, a source of primary current for said transformer, a circuit connecting different turns of the secondary of said transformer to said anodes, and a turn of said secondary approximately midway between said different turns of said secondary to said cathode,

for supplying operating current for said tube, and means connected to said secondary in parallel to said anodes for maintaining an approximately uniform tube voltage throughout large fluctuations of voltage in the primary current, and also maintaining a high power factor in said primary current,

9. In a lighting system for a gaseous illuminating tube of the alternating current, rectifying 'type, using a plurality of anodes and a cathode,

the combination with said tube of a leakage type transformer, a sourceof primary current for said transformer, connections from the secondary of said transformer to said anodes and from an intermediate point of said secondary to said cathode, and means including a two electrode condenser and a resonance controlling element connected to said transformer in parallel to said anodes for maintaining a high power factor in said primary current, and also maintaining an approximately uniform anode voltage under wide variations in the voltage of said primary current.

10. In a lighting system fora gaseous illumi nating tube of the alternating current, rectifying typehaving a plurality of anodes and a oath ode, the improved method of operating the'same which comprises transforming by loose coupling an alternating primary current into an operating alternating current, of suitable voltage, passing said operating current through said tube between said anodes and said cathode, correcting the phase angle and power factor of said operating current by capacitance at a voltage different than impressed on said anodes, for maintaining a high power factor in said primary current, and modifying the operating current to maintain an approximately uniform anode voltage under wide variations in the voltage of said primary current.

11. In a lighting system for a gaseous illuminating tube of the alternating current type, using a pair of anodes and a cathode; the combination with said tube of a leakage reactance type transformer having a primary winding and a secondary winding, a connection from an intermediate point of said secondary winding to said cathode, connections from said anodes to said secondary winding at opposite sides of said connection to the cathode, for delivering an operating current to said tube, means connected a pair of anodes and a cathode, the combination with said tube of a leakage reactance type transformer having a primary winding and a secondary winding, a connection from an intermediate point of said secondary winding to said cathode, connections from said anodes to said secondary winding at opposite sides of said connection to the cathode, for delivering an operating current to said tube, and means including a condenser connected to said secondary winding in parallel to said anodes for correcting the phase angle and power factor of said operating current and controlling the resonance of the circuit for the operating current through the secondary winding of said transformer.

13. In a lighting system for a gaseous illuminating tube of the alternating current type, using a pair of anodes and a cathode, the combination with said tube of a leakage reactance type transformer having a primary winding and a secondary winding, a connection from an interme diate point of said secondary winding to said cathode, connections from said anodes to said secondary winding at opposite sides of said connection to the cathode, for delivering an operating current to said tube, a two electrode condenser, wires connecting said condenser to said secondary winding in parallel to said anode connections, and means associated with the circuit including said condenser, the secondary winding and the wires connecting said condenser to said secondary winding, for controlling the resonance of said condenser circuit and through it keeping the circuit for the operating current through said angel 14. In a lighting system for a gaseous illuminating tube of the alternating current type, using a pair of anodes and a cathode, the come binationwith said tube of a leakage reactance type transformer having a primary. winding and a secondary winding, a connection from an intermediate point of said secondary winding to said cathode, connectionsfrom said anodes to said secondary winding at opposite sides of said connection to the cathode, for delivering an operating current to said tube, a two electrode condenser, wires ccnnecting said condenser to said secondary winding in parallel to said anode connections, and means associated with the circuit including said condenser, the secondary winding and the wires connecting said condenser to said secondary winding, for impressing on said condenser a voltage difierent from that impressed on said anodes.

15. In a lighting system for a gaseous illuminating tube of the alternating current type, using a pair of anodes and a cathode, the combination with said tube of a leakage reactance type transformer having a primary winding and a secondary winding, a connection from an intermediate pointof said secondary winding to secondary winding out of resonsaid cathode, connections from said anodes to coupling an alternating primary current into an operating alternating current, of suitable voltage, passing said operating current through said tube between said anodes and said cathode, correcting the phase angle and power factor of said operating current by capacitance applied directly in parallel to said anodes, for maintaining a high power factor in said primary current, and modifying the operating current to maintain an approximately uniform anode voltage under wide variations in the voltage of said primary current.

17. In a lighting system, a gaseous illuminating tube of the double anode, single cathode, low voltage type, a transformer having primary and secondary windings, means connecting spaced turns of said secondary winding to said anodes, means connecting the cathode of said tube to an intermediate point of said secondary winding, whereby current induced in said secondary winding will pass through said tube, and a v mary and secondary? windings, with the end-v p9;-

tions or its 'secon'dai'y winding connected 'tb sam anfliesmea e tin n in c me point of saidlsecondatiwindingto the cathode oisaid tube, fend ,ggrcenaciti element connected to the same seconderiwinding in parellel to-said anodes ei j iii w rfictorwkfi ng 20; In/a light gvsyst em; a ge seous il luminatingftnhegot thef double Jenode single cathode,

1o ldwIvq t 's ype; l n fq er -Yvi eep i a y 

